2. Create a flow service called “addSolution”
This service should contain one service from the WmRoot package: wm.server.ui:addSolution with the input: path to your “callback” service

3. Create a flow service called “removeSolution”
This service should also contain one service from the WmRoot package: wm.server.ui:removeSolution with the input: path to your “callback” service

4. Lastly we need to make sure that the solution is added to the IS Admin page every time the package gets reloaded
In your manifest.v3 file at the root of your package (example: MYPACKAGE/manifest.v3) there is a line like this:

<null name="startup_services"/>

This needs to be changed to:

<null name="MYPACKAGE.processing:addSolution"/>

5. Run the “addSolution” service once
The link to your solution should now be visible in the IS Admin (after a refresh)